syzbot

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BUG: KCSAN: data-race in touch_atime / touch_atime

write to 0xffff8881193563d0 of 4 bytes by task 3489 on cpu 1:
 inode_set_atime_to_ts include/linux/fs.h:1625 [inline]
 inode_update_atime fs/inode.c:2095 [inline]
 inode_update_time fs/inode.c:2153 [inline]
 generic_update_time fs/inode.c:2186 [inline]
 touch_atime+0x1d7/0x330 fs/inode.c:2264
 file_accessed include/linux/fs.h:2263 [inline]
 shmem_file_read_iter+0x477/0x540 mm/shmem.c:3499
 lo_rw_aio+0x67d/0x730 drivers/block/loop.c:-1
 do_req_filebacked drivers/block/loop.c:-1 [inline]
 loop_handle_cmd drivers/block/loop.c:1926 [inline]
 loop_process_work+0x56c/0xac0 drivers/block/loop.c:1961
 loop_rootcg_workfn+0x22/0x30 drivers/block/loop.c:1992
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4cd/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x6bc/0x8b0 kernel/workqueue.c:3421
 kthread+0x22a/0x280 kernel/kthread.c:467
 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff8881193563d0 of 4 bytes by task 30 on cpu 0:
 inode_get_atime_nsec include/linux/fs.h:1610 [inline]
 inode_get_atime include/linux/fs.h:1616 [inline]
 inode_update_atime fs/inode.c:2089 [inline]
 inode_update_time fs/inode.c:2153 [inline]
 generic_update_time fs/inode.c:2186 [inline]
 touch_atime+0x16c/0x330 fs/inode.c:2264
 file_accessed include/linux/fs.h:2263 [inline]
 shmem_file_read_iter+0x477/0x540 mm/shmem.c:3499
 lo_rw_aio+0x67d/0x730 drivers/block/loop.c:-1
 do_req_filebacked drivers/block/loop.c:-1 [inline]
 loop_handle_cmd drivers/block/loop.c:1926 [inline]
 loop_process_work+0x56c/0xac0 drivers/block/loop.c:1961
 loop_workfn+0x31/0x40 drivers/block/loop.c:1985
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4cd/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x6bc/0x8b0 kernel/workqueue.c:3421
 kthread+0x22a/0x280 kernel/kthread.c:467
 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0x37dc6068 -> 0x38a34645

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 30 Comm: kworker/u8:1 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: loop5 loop_workfn
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